20545531 has 2 divisors, whose sum is σ = 20545532. Its totient is φ = 20545530.

The previous prime is 20545493. The next prime is 20545573. The reversal of 20545531 is 13554502.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20545531 is a prime.

It is a super-2 number, since 2×20545531² = 844237688143922, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 20545496 and 20545505.

It is not a weakly prime, because it can be changed into another prime (20545331) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10272765 + 10272766.

It is an arithmetic number, because the mean of its divisors is an integer number (10272766).

Almost surely, 2^20545531 is an apocalyptic number.

20545531 is a deficient number, since it is larger than the sum of its proper divisors (1).

20545531 is an equidigital number, since it uses as much as digits as its factorization.

20545531 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 3000, while the sum is 25.

The square root of 20545531 is about 4532.7178381188. The cubic root of 20545531 is about 273.8876544058.

The spelling of 20545531 in words is "twenty million, five hundred forty-five thousand, five hundred thirty-one".